Voluntary disclosure literature suggests that in evidence games, where the informed sender chooses which pieces of evidence to disclose to the uninformed receiver who determines his payoff, commitment has no value, as there is a theoretical equivalence of the optimal mechanism and the game equilibrium outcomes. In this paper, we experimentally investigate whether the optimal mechanism and the game equilibrium outcomes coincide in a simple evidence game. Contrary to the theoretical equivalence, our results indicate that outcomes diverge and that commitment has value.